Brake-operating mechanism.



E. s. MEAD. BRAKE OPERATING IVIECLIMHSNI.`

APPLICATION FILED JULY 20. l9l4.

Pt-n Apr. 1919 2 SHEETS-SHEET l- Y E. MEAD.- Y

BRAKE OPERATING MECHANISM.

APPLICATION FILED JULY 20L 1914.

` LSLQQ., Patented Apr. 22,4919.

' 2 SHEETS-SHEET 2.

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end 28 of the piston rod is pivotally connected as by the connection QQwith the operating arm 18 so that when the piston is elevated, as will be later described, the operating arm will be raised and the brakes released. l

The piston is operated by some incompressible fluid, oil being preferably ein ployed. A supply of oil is maintained in a compression tank 31 which is connected by piping to be now described with an inlet 32 into the cylinder. The piping forming this connection consists, in the present instance, of a conduit 33 leading from the tank 31 to a manually operable control valve 34, a conduitv 35 leading from the valve 34 to an automatically operable valve 36 and a conduit 37.1eading to the inlet 32. The valves 34 and 36 are so arranged that both must be open to permit the introduction of oil or other fluid 'from the tank 31 to the cylinder 21. The valve 34 is connected by a conduit 38 with a sump or reservoir 39 and a simi lar connection 41 is provided between the valve 36 and the sump. When either valve 34 or 36 cuts ofi' communication, as will be later described', between the tank 31 and cylinder 21, the oil which is in the cylinder 21 returns either through the pipe 38 or 41 to the sump 39. From the sump 39 it is pumped by a suitable pump 42 into the ltank through c0nduits43 and 44, permitting v thereby the continuous use of, a relatively small quantity of oil. Oil leaking either at the valves or in the cylinder will also beV conveyed to the sump, the oil leaking in the valves being conveyed by the pipes 38 and 41 and the oil leaking in the cylinder past the piston through a connection 45. This connection takes in to the upper portion of the cylinder and adjacent the upper limit of travel of the piston. In the piston an annular recess 46 is provided in which the oil seeping past the contact faces of the piston and cylinder will collect and from which it will be received into the connection 45, the recess 46 and intake of the connection 45 being arranged so that they communicate when the piston is inupper position.

The valve construction is shown in an enlarged scale in Figs. 3 to 6 inclusive. The two valves 34 and 36 are exact duplicates of each other and the following description will apply to either. A. casing 51 is provided through which extends an opening 52, the bounding surface of which forms a seat for' a cylindrical longitudinally movable valve 53. Extending into the bottom oi the casing on opposite sides are two openings 54 and 55, one, 54, being adapted to be connected with the compression tank and the other, 55, with the operating cylinder. Two recesses, 56 and 57, communicate respectively -with the openings 54 and 55. These recesses are disposed'one above the other between the openings 54 and throughout their length by ports 59 and (il,

with the interior of the casing. The ports 59 and 61 are adapted to' be thrown into communication through recesses 62 provided in the cylindrical face of the valve 53. The varying cross-sectional area of the recesses is provided so that the oil may leave simultaneously from the recess 56 throughout the entire length of the port 61, the recess being larger nearer the inlet and diminishing toward the ends of the outlet port so that an even distribution of oil through the port may occur, -the varying size of the recess 57 which receives the oil through the port 59 permitting the oil to flow in and increase in volume as it approaches the opening The valve 53 is provided with a number of apertures 63 and the casing is closed at its top and bottom by plates 64 and 65 and the 4bottom one of which is provided with an outlet 66 to the sump. Any leakage in the valve will flow down through the outlet either beneath the valve or over its top and down through the apertures 63. The valve isdisposed in upper position or that shown in 'F ig. 4 when communication is desired lVhen, however, it is desired to break this connnunication and to permit the brake to set, the

valve is moved downwardly so that only the port 61 communicates with the recesses 62 -in1 the valve and the opening 53 is thereby thrown into con'miunication with the said outlet 66 over the top of the valve and down through the apertures 63, as will be readily appreciated by viewing F ig. 4.

The valve 36, which is the automatically operable valve, may be controlled in any prei-'erred or usual manner to bring it 'into operation to cut ott' communication between the com pression tank and the operating cylindcr at desired points lin the travel of the cage or platform to the hoist. In the present instance, however, it is shown as controlled by an electromagnet 71. The stem ot the valve carries an armature 72, the armature and magnet being so arranged that when the cage (not shown) reaches a predetei-mined point in its travel, either the arma. ture is attracted and the valve thus closedI or the magnet becomes denergized and proJ duces thereby a resulting movement of the valve to eut o communication between the Smil @Jj/hurl ful f f'nve :mi sump.

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